Much outdoor cooking over charcoal is conventional grilling in which meat, such as ground beef patties, steaks, chicken parts, and pork chops, or fish are placed on a grill directly over hot, glowing charcoal. Satisfactory cooking of ground beef patties, relatively thin cuts of meat, and fish can be carried out in this manner, at relatively high temperatures, in a few minutes to about one-half an hour.
Larger cuts of meat, such as beef briskets, pork shoulders, as well as whole chickens and the like, require much longer cooking times, sometimes up to twelve hours or more, depending on a number of factors, including the kind of meat being cooked, the size and weight of the portion being cooked, and its collagen content. Slow cooking of these meats breaks down collagen, making the meat tender, and easy to cut and chew. Because of the long cooking times, cooking must be carried out at relative low temperatures in order to avoid charring and dehydration.
Smokers are used for outdoor cooking of these larger cuts of meat. Most smokers fall into either of two categories. One popular type of smoker is typically in the form of a cylindrical or egg-shaped enclosure symmetrical about a vertical axis. In this type of smoker a charcoal or wood fire is directly underneath the meat rack, but vertically spaced from the meat rack by a large distance, usually with a drip pan interposed between the fire and the meat rack. Hot gas from the fire passes around the edge of the pan and into contact with the meat on the meat rack, and then out through a vent or chimney at the top. Another type of smoker has a cylindrical drum-shaped cooking chamber generally symmetrical about a horizontal axis, and a separate fire box attached to one end of the drum. Smoke from the firebox is directed into the cooking chamber, and, from the cooking chamber through a stack located near the opposite end of the cooking chamber. In the operation of both types of smokers, the temperature within the cooking chamber is controlled by manual adjustment of air dampers.
Indirect heating of larger cuts of meat can also be carried out in a conventional kettle grill, or a drum-type grill, by arranging the charcoal so that it is not directly underneath the meat, and adjusting the air dampers, both below the charcoal and above the meat, in such a way as to avoid excessive temperature.
In smokers, and also in kettle grills, it is difficult to maintain a steady, moderate temperature. Depending on conditions, the temperature in the smoker or grill will gradually rise or fall. Controlling the temperature, therefore, requires frequent adjustment of the dampers. If the fire becomes too hot, the meat will be cooked too quickly on the outside and inadequately on the inside. Moreover, if the fire is excessively hot, it will burn too quickly, requiring frequent addition of fuel. Excessive temperature can be avoided by using only a small amount of fuel. However, when a smaller amount of fuel is used, more frequent addition of fuel is required. On the other hand, if the dampers are insufficiently open to maintain combustion, the fire will be extinguished, and must be reignited. In either case, whenever the smoker or grill is opened to add or reignite fuel, the atmosphere inside the cooking chamber cools, and the proper cooking temperature must be reestablished.
Another problem encountered in conventional slow cooking is the excessive consumption of fuel. In order to establish a good charcoal fire, the usual practice is to ignite a quantity of charcoal, using lighter fluid, an electric heater, or a propane torch, or to place the charcoal temporarily in a removable chimney, and ignite it by burning paper. When these methods are used, the entire quantity of charcoal is ignited, and before cooking is begun, the charcoal is brought to a condition in which the coals are glowing, with little or no visible flame. A large amount of heat, and consequently a large amount of fuel, is wasted in the process of establishing a fire. The fact that the entire mass of charcoal is ignited initially, also means that it will be necessary to replenish the fuel supply from time to time, if cooking is to take place over a long interval.
An object of this invention is to make it possible to cook slowly with a solid fuel fire over a long time interval, without the need for constant attention to the fire. Another object of the invention is to conserve solid fuel, and to minimize or avoid the need for replenishment of fuel in slow cooking.